1820133221 has 8 divisors (see below), whose sum is σ = 1918076544. Its totient is φ = 1723757200.

The previous prime is 1820133199. The next prime is 1820133239. The reversal of 1820133221 is 1223310281.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1820133221 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1820133281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 389441 + ... + 394086.

It is an arithmetic number, because the mean of its divisors is an integer number (239759568).

Almost surely, 2^1820133221 is an apocalyptic number.

It is an amenable number.

1820133221 is a deficient number, since it is larger than the sum of its proper divisors (97943323).

1820133221 is a wasteful number, since it uses less digits than its factorization.

1820133221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 783651.

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 1820133221 is about 42663.0193610344. The cubic root of 1820133221 is about 1220.9589390204.

The spelling of 1820133221 in words is "one billion, eight hundred twenty million, one hundred thirty-three thousand, two hundred twenty-one".